Flutamide adverse effects

The adverse effects of antiandrogens are gynecomastia, hot flushes, GI disturbances, liver function test abnormalities, and breast tenderness. GI disturbances consist of diarrhea for flutamide and bicalutamide and nausea or constipation for nilutamide. Flutamide is also associated with methemoglobinemia, whereas nilutamide causes visual disturbances (impaired dark adaptation), alcohol intolerance, and interstitial pneumonitis. 

In 44 women with polycystic ovary syndrome treated with finasteride or flutamide for 6 months the adverse effects of flutamide were reduced libido, gastrointestinal disorders, and dry skin (29). Finasteride caused reduced libido, headache, and dry skin. Dry skin was reported in 68% of users of flutamide and in only 27% of users of finasteride. 

Gastrointestinal effects are common when flutamide is used to treat advanced cases of prostate cancer. At doses of 250 mg every 8 hours or 500 mg/day, 23 of 106 men had gastrointestinal problems, irrespective of the dosage regimen (45). There was no difference in the incidence of these effects in the 56 men who had previously received external beam radiation and 50 others who had undergone radical prostatectomy. This suggests that the gastrointestinal adverse effects of flutamide are not due to a local toxic effect. 

Cutaneous adverse effects of flutamide, which as a whole are common, include some cases of photosensitivity. 

Flutamide is a non-steroidal antiandrogen that is used to treat prostatic cancer. Its most common adverse effects are liver damage and photosensitivity. 

In 45 patients with prostatic cancer taking flutamide 250 mg tds, there was no evidence of methemoglobinemia (9). It is possible that anecdotal reports of this adverse effect are in patients with a particular susceptibility that was not represented in this study. 

Among 440 patients taking flutamide, gastrointestinal adverse effects (abdominal pain/distension, diarrhea, constipation, nausea/vomiting, and anorexia) occurred in about 22% (10). 

Themostcommon antiandrogen-related adverse effects are listed in Table 128-5. In the only randomized comparison of bicalntamide plus an LH-RH agonist versus flutamide plus an LH-RH agonist, diarrhea was more common in flutamide-treated patients. Antiandrogens can reduce the symptoms from the flare phenomenon associated with LH-RH agonist therapy. 

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